The present invention relates to improved alkanolamide surfactants and, more particularly, to modified monoethanolamides which are liquid at ambient temperatures and lower and to the method of making the same.
Nonionic surfactants are well known and have achieved fast growing commercial importance. They encompass a broad range of compounds having a diverse range of structures and applications. One type of nonionic surfactants are alkanolamides that are condensates, for example, of fatty acids with alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA) and monoisopropanolamine (MIPA), have been used in a variety of cosmetic, personal care, household and industrial formulations.
Alkanolamides are widely used in generally liquid systems such as liquid detergents and personal care products as foam stabilizers, viscosity builders, solubilizers and the like, in metal working formulations as lubricants, viscosity control agents, corrosion inhibitors and in a variety of other applications. Alkanolamides utilized as components in such systems are ethanolamides and/or isopropanolamides such as monoethanolamides, diethanolamides and isopropanolamides in which the fatty acid acyl radical typically contains from 8 to 18 carbon atoms. Such dialkanolamides are typically liquid, while monoalkanolamides are solids having melting points of 40xc2x0 C. to about 90xc2x0 C. Heretofore, especially satisfactory alkanolamides have been diethanolamides such as those derived from coconut oil mixed fatty acids or special fractions containing, for instance, predominately C12 to C14 fatty acids. These alkanolamides are generally liquid in form which greatly simplifies their use. For most applications, alkanolamides prepared from trialkylglycerides are considered most practical due to lower cost, ease of manufacturing and acceptable quality.
Up to now, monoalkanolamides have not been available in liquid form which has limited their use in many applications. In recent years, because of regulatory concerns and restrictions, formulation trends have been shifting toward greater usage of monoalkanolamides; such products being solids, are more difficult to handle and are inconvenient to use in large scale production processes. Accordingly, it would be highly advantageous to be able to combine the performance characteristics of monoethanolamides with products having liquid physical characteristics at below ambient conditions.
Another well known basic group of nonionic surfactants are the alkoxlated derivatives, primarily represented by polyethoxylated and polypropoxylated compounds which are widely used as emulsifiers and detergents but do not provide the advantages of alkanolamides in connection with, for example, foam stabilization and viscosity building. Attempts have been made in the past to use ethylene oxide as an adduction agent for alkanolamides to modify the properties of the alkanolamides in a favorable manner including possibly reducing the congealing temperature of the monoethanolamides. While ethylene oxide adducts of monoethanolamides were found to effect compositions with some modified congealing temperature properties, the amount of ethylene oxide needed to achieve such property changes in the monoethanolamides resulted in products having performance properties which more closely resembled those exhibited by polyoxyethylene compounds, and these derivatives did not retain many of the surfactant characteristics of alkanolamides which were most desirable.
It is accordingly an object of the present invention to provide a process for preparing modified monoethanolamide surfactant compositions having a congealing temperature less than about 15xc2x0 C., that preferably are liquids at ambient temperature and lower (e.g. 15xc2x0 C. or lower), and that exhibit the foam stabilizing, viscosity building and other desirable surfactant characteristics of unmodified dialkanolamide and monoalkanolamide surfactants.
It is another object of the present invention to provide a novel process for preparing an improved monoethanolamide surfactant composition by reacting a monoethanolamide surfactant composition having a congealing temperature of about 40xc2x0 C. or higher with an amount of propylene or butylene oxide sufficient to prepare a modified monoethanolamide surfactant composition having a congealing temperature of about 15xc2x0 C. or lower that substantially exhibits the surfactant characteristics of dialkanolamide surfactant compositions and the monoethanolamide reactant.
It is a further object of the present invention to provide improved modified monoethanolamide surfactant compositions having a congealing temperature lower than about 15xc2x0 C., that preferably is liquid at below ambient temperature and that exhibit foam stabilizing, viscosity building and the like characteristics of dialkanolamide and monoalkanolamide surfactants.
It is still a further object to provide cosmetic and other personal care preparations containing modified monoethanolamide surfactants having congealing temperatures of about 15xc2x0 C. or lower.
It is yet another object of the present invention to provide metal working and other compositions for a variety of household and industrial applications containing modified monoethanolamide surfactants having congealing temperatures of about 15xc2x0 C. or lower.
These and other objects will become apparent from the description to follow.
In accordance with the present invention there has now been discovered a novel process for preparing monoethanolamide surfactant compositions having congealing temperatures of about 15xc2x0 C. or lower which comprises:
a) providing a monoethanolamide composition mixture derived from triglyceride oils and fats represented by the formula 
wherein:
R is an optionally substituted or unsubstituted, branched or straight chain, saturated or unsaturated hydrocarbon radical of 3-21 carbon atoms; and
b) reacting said monoethanolamide composition mixture in the presence of a suitable catalyst with an amount of propylene oxide, butylene oxide or mixtures of the same sufficient to form a modified monoethanolamide surfactant composition mixture that is liquid at below ambient temperature, preferably having a congealing temperature of about 15xc2x0 C. or lower. In general, the reaction is carried out for a time sufficient for substantially all of the alkylene oxide to react.
In another aspect of the present invention there are provided modified monoethanolamide surfactant composition mixtures having a congealing temperature of about 15xc2x0 C. or lower the predominant component of which is a modified monoethanolamide represented by the formula 
Wherein:
R is an optionally substituted or unsubstituted, branched or straight chain, saturated or unsaturated hydrocarbon radical of 3-21 carbon atoms;
B is CH3 or xe2x80x94CH2xe2x80x94CH3; and
x is an average value of at least about 1 representing the ratio of moles of alkylene oxide selected from propylene oxide, butylene oxide and mixtures thereof to moles of monoethanolamide sufficient to prepare a monoethanolamide composition mixture having a congealing temperature of 15xc2x0 C. or lower.
Other components in such mixtures, are alkoxylated glycerin, glycerin and nonalkoxylated monoethanolamide the total amount of which generally ranges from 10% to about 55% by weight, the relative concentration of each of such additional components depending on the degree of alkoxylation of the reaction mixture and the monoethanolamide composition mixture from which the modified monoethanolamide composition mixture of the invention is prepared.
The modified monoethanolamide composition mixtures of the present invention which are liquids at lower than ambient temperature, preferably have a congealing temperature of about 15xc2x0 C. or, most preferably lower, surprisingly and unexpectedly generally exhibit most, if not all, of the surfactant characteristics of dialkanolamide surfactant compositions such as the foam stabilization and viscosity building properties, as well as retaining substantially all the favorable properties of the monoethanolamides from which the compositions are prepared.
In yet another aspect of the present invention, there are provided cosmetic and personal care compositions which comprise at least 0.1% by weight of a modified monoethanolamide surfactant composition mixture which is liquid at lower than ambient temperature, the predominant component of which is a modified monoethanolamide that may be represented by the formula 
Wherein:
R is an optionally substituted or unsubstituted, branched or straight chain, saturated or unsaturated hydrocarbon radical of 3-21 carbon atoms;
B is CH3 or xe2x80x94CH2xe2x80x94CH3; and
x has an average value of at least about 1 as hereinabove defined.
In a still further aspect of the present invention there are provided metal working compositions and household cleaning products which are in liquid form comprising at least 0.1% by weight of a modified monoethanolamide surfactant composition mixture which is a liquid at lower than ambient temperature, the predominant component of which is a modified monoethanolamide that may be represented by the formula 
Wherein:
R is an optionally substituted or unsubstituted, branched or straight chain, saturated or unsaturated hydrocarbon radical of 3-21 carbon atoms;
B is CH3 or xe2x80x94CH2xe2x80x94CH3; and
x is hereinabove defined.